A Floatable Concrete Block.

New Zealand Graphic, Volume XLV, Issue 12, 21 September 1910, Page 36

A Floatable Concrete Block.

Our picture illustrates a floatable concrete block, invented by Air J. E. Taylor. of Mangere, to be used m the construction of wharves, piers, docks, ietaining walls, etc., and for any concrete work below water. The concrete would be laid inside a caisson or huge box, made of steel plate, the sides, ends ami bottom of v hich are all bolted together with a watertight joint, and are th “efore all detachable, each section of th? caisson walls being sft high. In actual practice, the first section of the caisson w add be built on a san.l bed. formed on a beach, about 3ft below full tide h°ig’ii • its steel-plate walls at this -tage being sft nigh. A thin layer of cement mixrure would be poured in on to its bottom plate, ami large stones, packed in between with sma 11(1 ones, would be deposited on the cement, and those all jointed together w?L more flowing cement; a thickness of about 12in of th *se materials being so deposited. When the tile came in full, the caisson with its load would float in the three feet of water surrounding it. It would then be towed out into deeper water, and allow'd to settle with the failing tide on to a sand-bed formed three feet above low tide. Here another section of steel wall-plate would be bolted on. making the total depth of the caisson 10ft. Alore large and small stones could now be deposited in the caisson, and cemented together as before, until a total thickness of three feet of this mass was laid on its bottom. The first layer of cement now having set hard, the bolls attaching the steel bottom plate Io the caisson could be removed while Ihe tide was out. When tin tide came in again, it would float the caisson in Bft of water, with its load of 3ft thick of stone, etc., and its -teel bottom plate would be left on the sand, so that it could be recovered for tint her u-e when the tide went out. The caisson would now be like a barge with steel sides 10ft high, and hard set. concrete three feet thick for its bottom. It would now be towed out into deeper water, and yet another section of steel wall-plate bolted on, making the caisson 15ft deep. The process after this being simply to alternately load the caisson with more such material or concrete, and then bolt on another section of steel wall-plate every time it was loaded, so deep that only two feet of the steel walls stood up above the water in which it floated. When the caisson had thus attained a sufficiently deep draught, it would be towed over its final restingplace, and allowed to settle gently on to its bed. where it would be completed by

filling up the caisson with stones, cement and <•<mcrete. \\ lien completed, a diver would unscrew the lxdt- v h’n-ii had f.is'eiied tilt* caisson together, that t’i<* w idp of the >teel plate wolli'l !>•> 'iaul“| Up i'»lin t her u>c in form -i g tin ais- «n again. Holes are moulded through the Lloclfrom bottom to top, and about aft apart.

for the purpose of inserting a hydraulic pipe with a nozzle at the end. This would be pushed through to the bed of the block, ami water, under great presetire. furred through the nozzle vertically and laterally to sluice away any silt or soft material which would conn* up l lie bole in solution, and allow the block l o set 11<* on a firm bed. Ilic block and caisson shown in our

illustration weigh about 12cwt. and it has been afloat for more than ten hours with the steel bottom plate removed, without showing any sign of leakage.

Blocks 50ft in length, and of correspond iiig width, can lx* made, and largely composed of stones weighing tip to a ton each. It is protected for patent.

\n unusual effect secured by good judgment and daring.

The picture shows a floatable concrete block, invented l»y Mr. .1. E. Taylor, of Mangere. being inspected by a number of Auckland officials. The principal embodied in this system of construction is fully explained in the accompanying article. The block shown is afloat in its caisson with the steel bottom-plate removed.